The production of shampoo, body soaps, hair conditioners and similar personal care products are an important segment of the health and beauty market. These products typically consist of water, surfactants, fragrances, and proprietary ingredients, and are ubiquitous throughout society. The manufacture of such products generally requires close quality control procedures, and a high standard of sanitary conditions, similar to that found in the food or pharmaceutical industry.
Many shampoo production facilities manufacture a number of similar products, usually in standard, batching operation. When production is switched between differing varieties it is not uncommon that all equipment must be drained, washed and rinsed. Waste from shampoo manufacturing typically is found in either a concentrated or dilute form. Concentrated shampoo waste (being similar to shampoo products) is generally derived from draining of lines, materials not meeting specifications, dated product, discontinued product, and formulation constituents. Diluted shampoo waste is generally the “rinse water” generated during formulation change over purging of lines, clean-up operations, and rinsing of equipment and tanks. The difference in the concentrated and dilute forms is in the percentage of residual shampoo product. Rinse waters typically have less than 10%, while concentrated forms of waste will have greater than 10%, and may essentially be 100% shampoo materials.
Disposal of the dilute rinse water is usually via the sanitary sewer, and hence to a Public Owned Treatment Works (POTW). The dilute waste will have a slightly elevated pH, elevated Biochemical Oxygen Demand (BOD), foam and odor. Large volumes discharged to the sewer system can negatively impact the POTW, through altering influent pH, creating excessive foaming especially in secondary aeration tanks, and consuming treatment capacity due to increased influent BOD values. These impacts are frequently offset by additional sewering charges paid by the discharger.
Disposal of the concentrate waste is more problematic, due to a very high pH and constituent concentrations that may exceed sewer discharge standards at best and hazardous waste definitions frequently. The concentrate may also be hazardous due to bioassay assessment. Shampoo waste concentrate is typically collected by the manufacturer and shipped off-site for disposal/destruction at appropriately permitted facilities.
The costs to the manufacturer for the disposal of both dilute rinse waste and concentrate waste is significant. Equipment and manufacturing designs help assure that, minimal waste production occurs during batch changing operations, and quality control procedures help minimize the frequency of out of specification materials. Still, significant volumes of waste material are generated annually.
Portland cement manufacturing is a world wide industry with cement kilns located throughout the world. Over 100 million tons of cement is produced annually. Cement manufacture uses a variety of minerals, which when blended, ground and calcined form a intermediate product known as cement clinker. Calcium aluminum, iron, and silica are the primary elemental components of cement clinker. Clinker is finely ground with a small percentage of gypsum-added to produce ordinary portland cement (OPC). Cement specifications designate the chemistry and attributes of the cement. Cement, when mixed with water, sand and possibly an aggregate, cures to form a hardened material called concrete. Concrete with no aggregate is often referred to as grout or mortar. The American Society for Testing and Materials (ASTM) identifies a number of cement types, each with a differing set of performance specifications.
Materials added to the OPC during grinding operations or added when concrete is being prepared can impart specific characteristics of value to the builder. One of the functional additions is air entraining admixtures (AEA). AEA can be added during the grinding of cement clinker, or added to OPC as part of the concrete recipe. AEA materials form small air bubbles in the concrete matrix while in the wet stage, which are maintained through hardening and curing. Air entrained concrete is superior to concrete formed from OPC for applications where frost resistance is important, when used as a mortar, in stucco, or where workability is important. Air entrained portland cement is a value added material, being sold at prices well above OPC.
Air entrained portland cement and air entrainment admixtures have been widely used throughout the cement industry since the early 1950's. There are a number of types available commercially, with specific formulations either patented or proprietary in nature. Materials used as AEAs include 1. The salts of wood resins; 2. Synthetic detergents; 3. Salts of sulfonated lignin; salts of petroleum acids; fatty or resinous acids and their salts. The manufacture of air entrained portland cement and air entrained concrete is a well known and accepted art.
Air entrainment is measured as a percentage of air in a specifically prepared mortar sample. Test protocols are well established such as in ASTM C185, “Test Method for Air Content in Hydraulic Cement Mortar”. For reference purposes OPC will often have about 6% air entrained, while an AEA portland cement will often have up to 25% air entrainment. The manufacture, based on intended use and performance criteria determines the percentage of entrained air.
Further information relating to concrete can be found in the work titled “Concrete Materials—Properties, Specifications, and Testing” by Sandor Popovics and published by Noyes Publication in 1992 (herein incorporated by reference in its entirety).